We can use ABAP classes in the definition and runtime components of SAP WebFlow Engine in the same way as object types defined in the Business object Repository (BOR). Before proceeding further we need to know where to create and maintain ABAP Classes and ABAP Interfaces.
What is Class Builder and its purpose?
The Class Builder allows us to create and maintain global ABAP classes and interfaces. Both of these object types, like global data types, are defined in the ABAP Repository, thus composing a central class library. Together, they form a central class library and are visible throughout the system.